The invention relates to a geotextile tube connecting unit for insertion into, or connection of a flushing tube to, a filling opening in a geotextile base fabric or for insertion of the flushing tube therein. The unit comprises at least a flange ring, a support ring and connection means for the connection of the flange ring to the support ring, including the geotextile base fabric positioned therebetween.
Geotextiles are used in numerous fields of applications in civil engineering and engineering construction. Favorable properties are the high mechanical tensile strength and the permeability to water. This results in applications such as the dewatering of sludge, the shoreline stabilization or the use as a wave breaker in coastal protection. In these applications, very large, in particular tube-shaped, containers are formed from geotextiles, which are filled with a suspension through a filling opening via flushing tubes. The solids of the suspension sediment within the containers, and the water contained therein can escape through the geotextile wall. The ends of the flushing tubes are either inserted through a filling opening and are thus guided directly into the interior of the container or are provided with coupling means that are connected to compatible coupling means at the filling opening. With a container diameter of several meters, high hydrostatic pressures occur during filling that lead to high tensile stresses in the jacket. Although geotextiles are readily able to absorb these tensile stresses, the filling openings represent weak spots. In any case, it is necessary to guide the considerable tensile stresses in the geotextile around the filling opening and to prevent the geotextile from starting to and continuing to tear at the filling opening.
U.S. Pat. No. 8,088,117 B describes a tube connecting unit of the type in question for a flexible container. In this case, the filling tube is provided with a fixed neck at the end, which has a flange. A flange ring is placed around the filling opening in the textile fabric section. This can be connected on the one hand to the flange of the tube neck; on the other hand, it interacts with a support ring on the other side of the fabric section. Screws pass through openings in the fabric to connect the flange ring and the support ring to each other. To prevent the edge section of the fabric extending around the filling opening from being pulled out from the clamping between the flange ring and the support ring, supplementary elastomeric rings are provided, which are intended to reinforce the frictional clamping between the flange ring and the support ring. However, in view of the high tensile stresses in suspension-filled containers, the frictional clamping of the geotextile section can fail, with the fabric still being form-fittingly retained on the screws. Due to the high stress concentration at the screws, however, a tear in the geotextile would soon develop.
U.S. Pat. No. 6,623,214 B1 describes a geotextile tube being used in coastal protection and describes a repair kit with which already formed tears are to be caught and further tearing is to be prevented. A filling opening is not provided; rather, a cover is used as the counterpart to a flange ring. The flange ring and the cover are also connected to each other using screws that are inserted through openings in the fabric. The fabric is clamped between the flange ring and the cover; supplementary friction-increasing rings are provided here as well. This too has the disadvantage that the frictional attachment can fail, and that a form-fitting attachment via the screws leads to initial and then continued tearing because of the stress concentration at the openings in the fabric.